The Huisgen 1,3-dipolar cycloaddition of alkynes and azides to form 1,4-disubstituted-1,2,3-triazoles has been established as one of the most reliable means for carbon-heteroatom bond forming “click chemistries”. The term “click” reaction generally refers to a reaction that is high yielding, stereospecific for a single product, and easy to perform with regard to starting materials, solvent, or product isolation. “Click” reactions are invariant to the presence of air or moisture, and tolerant to a wide range of functional groups. See for example, a recent “click chemistry” review by Kolb H. C. et al, Angew. Chem. Int. Ed. 2001, 40, 2004-2021. Also, see Huisgen R., Proc. Chem. Soc. 1961, 357-369, and Huisgen R., Angew. Chem. 1968, 80, 329-337.
The present invention discloses novel triazole-based monomers synthesized via a “click chemistry” approach. In particular, the present invention describes a group of novel (meth)acrylates containing 1,2,3-triazole moieties. The new (meth)acrylate monomers may be formed via the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of azides with acetylenic (meth)acrylic esters such as propargyl acrylate. These “click” reactions give access to a new monomer family of triazole-based (meth)acrylates.
The literature discloses numerous references where macromers or dendrimers, prepared via atom transfer radical polymerization (ATRP) or other controlled polymerization methods, are derivatized to contain azido end-groups. Reaction of the azido-terminated macromers with alkyne-containing (meth)acrylates results in the formation of derivatized end-capped macromers containing (meth)acrylate functionalized 1,2,3-triazoles. For example, see Vogt A. P. et al, Macromolecules 2006, 39, 5286-5292, and Liu Q. et al, J. of Polymer Science: Part A: Polymer Chemistry, vol. 44, 6103-6113. Furthermore, Opsteen J. A. et al, Chem. Commun., 2005, 57-59, discusses the modular synthesis of block co-polymers via 1,3-cycloaddition of terminal azides with alkyne-functionalized polymers. Also, in Macromolecules 2005, 38, 7540-7545, Sumerlin B. S. et al reports the use of the highly efficient “click” reaction to prepare poly(triazoles) by coupling poly(3-azidopropyl methacrylate) with alkynes.
U.S. Pat. No. 7,208,243 discloses azide-alkyne cycloaddition reactions to prepare cross-linked polymers. The cross-linked polymers may be formed from a first alkyne functionalized polymer and a second azide functionalized polymer, a single polymer species which may include both azide and alkyne groups and cross-links with itself, or a polymer with azide groups and a non-polymer compound including one or more alkyne groups. Similarly in J. of Polymer Science: Part A: Polymer Chemistry 2004, 42, 4392-4403, Diaz D. D. et al employs the coupling of polyvalent azides and alkynes to make cross-linked polymeric networks of 1,2,3-triazoles, with good adhesion to metal surfaces.
U.S. Application Publication No. 2007/0066762 discloses triazole-containing perfluorinated acrylic monomers. The monomers are co-polymerized for imparting water repellence and stain resistance to substrates.
Furthermore, Riva R. et al, ARKIVOC 2007, 10, 292-306, discloses acrylates formed by 1,3-cycloaddition of various alkynes with 5-azidooxepan-2-one.
There exists however, a continuing need for novel monomers such as those presently described.